Various known devices provide for the controlled dispensing of medical fluids. Furthermore, some are adapted to provide suction as well as irrigation at the dispensing tip. The suction is generally suitable for the removal of fluids during surgical procedures.
Examples of medical devices which are adapted to dispense fluid as well as provide vacuum at the working tip are disclosed in U.S. Pat. Nos.: 3,065,749; 3,469,582; 4,397,640; 4,573,979; 4,617,013; 4,696,669; 4,708,717; 4,776,840; 4,857,047; 5,061,180; and 5,226,877. Some of these devices have a suction pathway which is distinct from their dispensing pathway, such as those disclosed in U.S. Pat. Nos.: 3,065,749; 4,397,640; 4,573,979; 4,617,013; 4,696,669; 4,708,717; 4,857,047; 5,061,180; 5,226,877. Alternatively, some use the same pathway to either provide suction or dispense fluid, such as the devices disclosed in U.S. Pat. No. 3,469,582 and 4,776,840.
Referring to U.S. Pat. No. 4,776,840 to Freitas, a device is disclosed which has a suction outlet adjacent a dispensing outlet which may also provide suction in parallel to the suction outlet. In order to provide suction at the working tip, the user depresses a plunger which connects the vacuum source to the dispensing outlet pathway in addition to the suction pathway. In contrast, if the user desires to dispense fluid, the user pulls a trigger switch which is in communication with a piston. As the trigger is displaced, the piston is displaced and pushes fluid through a check valve leading to the dispensing outlet pathway.
In addition, devices adapted to dispense tissue adhesives or sealant are disclosed in U.S. Pat. Nos.: 4,040,420; 4,359,049; 4,735,616; 4,874,368; 4,978,336; 5,116,315; 5,226,877; 5,368,563; 5,474,540; and 5,605,541. Typically, these known devices have two self-contained fluid reservoirs. Each reservoir has an outlet passageway which may lead to a common passageway in which the fluids mix. In many tissue adhesive applications, a fibrinogen solution is mixed with a thrombin solution to start the clotting process and form the physiological adhesive or sealant. Often, the mixture that remains in the mixing passageway commonly causes clogging of the dispensing tip. To overcome this obstacle, some devices have been developed to spray the independent components of a two part biological adhesive so that mixing occurs in the spray between a device nozzle head and the tissue. Examples of such spraying devices are disclosed in U.S. Pat. Nos. 5,368,563 and 5,605,541.
Finally, disclosed suction and medical dispensing devices provide very limited volume indicators, such as visual volume indicators on the working device which require the user's attention to be diverted from the working area of fluid dispensing. An alternative volume indication mechanism is disclosed in U.S. Pat. No. 5,226,877 to Epstein. Epstein discloses a medical dispensing device that has an audible loudness indicator which provides discrete audible "clicks" at predetermined incremental volumes of fluid delivery. However, this beneficial indicator does not audibly indicate the cumulative volume of fluid dispensed, but instead requires a user to remember the number of clicks.
There is still a need for an audible loudness indicator which emits audible signals to a user that indicate the cumulative volume of fluid dispensed at each incremental volume of fluid delivery.
There is also still a need for an apparatus and method for withdrawing a cast of cured tissue adhesive or other congealing fluid from the dispensing conduit in the tip of a medical fluid applicator.